Such an apparatus may be constructed, for example, as a vacuum cleaner comprising a vacuum cleaner body with a hose provided with a nozzle coupled to the air inlet of the vacuum cleaner body, which body comprises a dust chamber in communication with the air inlet and a housing for a fan driven by an electric motor, which housing is in communication with the dust chamber and the air outlet. Such vacuum cleaners may be of the type commonly referred to as upright or canister. The usual canister-type vacuum cleaners have bodies with front portions having blunt, rounded shapes which are normally pulled along by a hose during cleaning. This blunt body shape often gets blocked or snagged or rendered immobile behind furniture parts such as chair and table legs, for example, forcing the user to interrupt vacuum cleaning to free the vacuum cleaner before cleaning can be resumed.
Such an apparatus is known from EP 0 420 265 and its related patent EP 0 558 101 A2, which relate to such vacuum cleaners adapted to avoid obstacles on a cleaning surface to be cleaned even if the outer contour of the cleaner body is generally flat. The disclosed vacuum cleaners comprise an angularly movable traveling member angularly mounted on the cleaner body to be angularly movable around an outer wall of the dust collector chamber, or a swinging plate which constitutes part of the traveling member, has casters and is mounted by a shaft on a lower front surface so as to be angularly movable about the shaft. The angular member has a bumper that is first caused to collide with the obstacle. When the suction hose is pulled further, the bumper is angularly moved together with the angularly movable member to turn the cleaner body in a direction away from the obstacle and to move it to a position whereby the obstacle can be avoided. In a second embodiment, a swinging plate is movable right and left about a shaft portion and a spring member mounted on the swinging plate produces a spring force for angularly returning the swinging plate to its initial position when the swinging member is angularly moved. The swinging plate is held in a neutral position when the obstacle does not collide with the swinging plate. In addition to requiring numerous and intricate parts and the accompanying expense of manufacture, these vacuum cleaners do not utilize an actively controlled driving or direction control. The castor wheels, for example, are not actively controlled to achieve, at the point in time of obstacle touch or obstacle sensing, a resultant velocity away from the obstacle, and are not adapted to achieve this result when subjected to arbitrary forward velocities such as those that a user imposes by pulling the vacuum by the hose. Moreover, there is no detection of obstacles for avoidance and thus reduced wear and tear on the vacuum cleaners.
There is a need for a vacuum cleaner of the type described above which will embody the characteristics of:
(1) robust obstacle detection and display or robust obstacle detection and avoidance or robust obstacle detection, display, and avoidance and PA1 (2) non-contact or minimal contact sensing PA1 (3) simple electronics and mechanics PA1 (4) low cost PA1 (5) the ability to retrofit existing designs.